Prune trees in the “R” months

 Pruning unnecessary or unwanted branches from yard or forest plantation trees is a common practice. In homeowner settings, branches are sometimes removed because they obstruct buildings or infringe on the chore of mowing. In forest plantation settings, branches are removed so that crop trees can grow higher grade lumber, marketed for more valuable wood products.

One rule to remember when pruning trees involves the spelling of the names of the months, says David Mercker, forest management specialist with University of Tennessee Extension. “Prune during any month with an “R” in it,” he said. “This includes September, October, November, December, January, February and March.” During these months, trees are either progressing toward winter dormancy or are in winter dormancy. Their sap flow will be limited, which is important. Flowing sap from the new wound often attracts insects, which in turn, can be carriers of unwanted tree disease. Mercker said the exception to the pruning rule is April. During April most trees in this region are no longer dormant and their sap will flow freely.

         Following are recommended practices for healthy pruning:

• Prune branches while they are still small, preferably having a caliper of 1 inch or less. Try to anticipate which branches will need to be removed while the tree is still young.
• Do not prune flush to the tree trunk, nor leave an obvious stub; both of these will make healing difficult. Instead, prune to the edge of the branch collar (a slight swelling where the branch meets the trunk).
• Use a sharp saw, never an ax or hatchet. This will allow for a clean cut, which will heal more quickly.
• Prior to using the saw, clean it with rubbing alcohol. This will prevent the possible spread of disease from the tool to the tree.
• For larger limbs, make an “under cut” first on the branch to be removed. If you don’t, the bark directly under the stem may peel as it falls. This creates a larger wound.
• Do not paint the new wound. Healthy trees are capable of rapid cell division, soon enclosing the wound (called compartmentalization).
• Follow safety precautions, particularly when using a ladder or when pruning near utilities or structures.
• Finally, maintain favorable growing conditions following the pruning. In yard settings, this could include mulching, fertilization and protection of the soil and base of the tree.